Material mixing apparatus



April 3, 1951 w. M. MADSEN MATERIAL MIXING APPARATUS 2 Sheets-Sheet 1 Filed July 5, 1947 l'nwentor M A 05 E N WALTER (Itforneg April 3, 1951 w. M. MADSEN 2,547,403

MATERIAL MIXING APPARATUS Filed July 5, 194'? 2 Sheets-Sheet 2 Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE 6 Claims.

The present invention relates generally to material mixing apparatus such as utilized for the mixing of paving and road building materials; and is more particularly concerned with improved means for the proportioning and mixing of a binding agent with an aggregate such as crushed stone, gravel, or the like.

It is an object of the herein described invention to provide in a mixing plant or mixing apparatus for the mixing of materials such as utilized for paving, road building, and the like, improved means for measuring and introducing into the mixture a predetermined or measured quantity of binding agent so that a standardized product will be constantly maintained.

A further object of the invention is to provide improved mixing apparatus having parts so arranged that proportioned measured amounts of materials may be mixed, and wherein the introduction of these materials is speeded up and the mixing time shortened by accelerating the time required to introduce the materials into the mixture, particularly the time for introducing the binding agent.

Another object is to provide an improved structure for conducting the binding agent from a weighing receptacle and introducing it into an aggregate within a predetermined location in a mixer.

Still another object is to provide an improved arrangement, whereby certain parts of the measuring and conducting system for the binding agent may be retained in heated condition so as to facilitate handling of the binding agent.

Briefly, in carrying out my present invention, an aggregate weighing receptacle is arranged above a pug mill or mixer so that a predetermined quantity or amount of aggregate may be discharged directly into the mixer. A weighing receptacle is also provided for receiving and weighing a quantity of binding agent, such as the usually used bitumens, and the like, which in proper amounts to give the desired mixture may then be introduced by downward flow through a discharge conductor into the mixer at such locations as to be most effectively mixed with the aggregate. The mixing time will be dependent to a considerable extent upon the time required to introduce the binding agent, and in order that the speed of introduction may be augmented and speeded up, there is provided in the discharge flow passage of the binding agent a pump impeller which acts to speed up the discharge of binding agent and materially reduce the time of introduction over that which would be required if the binding agent were merely permitted to flow by gravity.

Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations on the scope of the invention defined in the appended claims.

Referring to the drawings, which are for illustrative purposes only:

Fig. l is a side elevational view of mixing apparatus embodying the features of my invention, parts being cut away to disclose important details and operative relationship of certain of the component parts;

Fig. 2 is an end elevation of the same, and showing, details of the weighing mechanism for the weighing receptacle forming a. part of the mechanism for introducing binding agents into the mixer part of the apparatus;

Fig. 3 is a sectional view, taken substantially on line 3-3 of Fig. 1;

Fig. 4 is a plan detail view of the mechanism for measuring and introducing the binding agent into the pug mill or mixer, parts being cut. away to more clearly disclose certain parts of the structure;

Fig. 5 is a modified construction of discharge conductors for the binding agent;

Fig. 6 is a transverse sectional view through the same, taken substantially on line 6-6 of Fig. 5; and

Fig. '7 is a plan view of another discharge conductor construction.

As generally illustrated in Fig. 1, there is disclosed a mixer-weigh box unit which embodies the features of the herein described invention.

This unit comprises an aggregate weigh box A supported above a pug mill or mixer B and a binding agent weighing and discharge mechanism as indicated at C. These elements, together with associated weighing mechanism and control members are associated and mounted in a skeleton frame structure to form an assemblage which may be handled, shipped, and installed as a unit part of a mixing plant. The frame structure consists of a substantially rectangular upper frame I0 in which side beams H I are interconnected by end beams I 2I2. The upper frame It is supported by corner post structures l3 secured and projecting upwardly from the corners of a bottom or base frame structure [4 in which side beams |5|5 are interconnected by end. beams iii-4G.

The weigh box A is suspended from the upper frame 10 and supported by weighing mechanism of conventional construction (not shown)- which permits the weighing of required amounts of aggregate in the weigh box by the operator. The

weigh box A is of conventional construction and has a flared bottom terminating in a discharge opening closed by a gate valve I! supported at its end for swinging movement to open and closed positions on pivots I8.

The mixer B comprises a hollow body H which forms a pair of mixing chambers in which parallel shafts 20 and 28a are rotatably mounted. These shafts are each provided with a plurality of mixing paddle assemblies 2| which are spaced along the shafts and project radially therefrom, the assemblies coacting to mix the material deposited into the mixing chambers. The hollow body [9 is open at its top where it is connected with a rectangular collar 22 of channel construction. The upper side of the collar 22 connects with the lower edge of a dust protective housing 23 of sheet metal construction which surrounds and encloses the lower end of the weighing box A so as to form a substantially enclosed connection between the weigh box and the interior of the mixer B.

The weighing and discharge mechanism for binding agent which is to be mixed with the aggregate will now be described. As shown in Figs. 1 and 4, for such purpose there is provided at one side of the housing 23 a binding agent receiving receptacle or box having a generally rectangular main body portion 24 provided with a bottom spout portion 25 arranged to project through an opening 26 formed in one side of the housing 23. The body portion 26 has an upwardly disposed open top for receiving therethrough the binding agent to be measured.

The sides of the body portion 24 are provided with angle side rails Zl2l having spaced apertures 28 for receiving suspension hooks 29 (Fig. 2) which cooperate to form a four-point suspension from a weighing mechanism.

A spacer pipe member 36 extending parallel with the adjacent rail 2'! is provided with spaced inwardly projecting lever arms 3| which are respectively connected at their outermost ends to the hooks 25, and at points spaced inwardly from the outer ends to suspension hooks 32 depending from the upper frame structure It. The outermost ends of the pipes 36-450 are respectively provided with lever arms 3333 which extend along the end of the body portion 24 and are associated with a common stirrup 34 having a connection at a point 35 on one end portion of a lever 38. The lever 36 is fulcrumed at 3'5 and suspended from the upper frame it. The other end of the lever 36 is connected through a rod connection 38 with one end of a lever 39 fulcrumed intermediate its ends at a point 411 and connected at its other end through a connecting rod M with weight indicating mechanism, including a suitable dial 52 and indicating hand 43.

The binding agent is supplied through an inlet conduit M having connection with an outlet conduit 45, these conduits being connected through a three-way valve 46 with a discharge pipe 41 extending into the open end 26 of the body portion 24. By means of an actuating lever 43, the valve may be positioned to permit continuous circulation of the binding agent, or when desired, permit the supply of binding agent to be directed through the discharge pipe 4'3 into the weighing receptacle.

Manual actuation of the three-way valve 46 is provided by connecting the lever 48 through a connecting rod 49 with a lever 56 carried at one end of a shaft 51 this shaft being connected at its .opposite end with a hand lever 52 positioned for easy reach of the attendant operator at one side of the unit. I

For controlling discharge of the binding agent from the inner end of the spout portion 25, there is provided a mushroom valve 53 as shown in Fig.4. This valve is connected to the outermost end of a lever 54 which is carried by a rotatively mounted shaft 55 and connected with an actuating lever at its other end, this lever being indicated by the numeral 56. The outermost end of the lever 56 is connected with a strap connector 5'! to a lever 58, as shown in Fig. 2. This lever is fulcrumed at one end and interconnected through a connecting rod 59 at its opposite end with a bellcrank 60 which is in turn connected through a connecting rod 6| with a lever 62 carried at one end of a tubular shaft 63 which surrounds and is rotatively supported with respect to the shaft 5|, the other end of the tubular shaft 63 being connected with a hand actuating lever 64 positioned adjacent the hand lever 52 for convenient actuation by the attendant.

There is also positioned adjacent the aforementioned hand lever a hand lever 65 which through suitable connection is operatively associated with mechanism for controlling the opening and closing of the gate valve I! for controlling admission of aggregate to the mixer.

The flow of binding material through the spout 25 is in a generally downward direction. This flow is augmented, and the introduction of binding agent into the aggregate is speeded up by the employment of a pump 65 of the impeller type having an impeller 61 arranged with its inlet connected to the outlet of the spout '25 and .its'outlet connected with a discharge conduit 68.

The impeller is connected through suitable drive, in this instance a shaft 69, extending through the collar member 22 and having a driving connec tion with power means in the form of an electric motor In suported outside the housing 23 where it will not be subjected to the heat within the housing 23. The motor is shown as being mounted on a suitable bracket on the bottom of the weighing receptacle for the binding agent. Suitable control for this motor, although not shown, may be positioned for convenient manipulation by the attendant operator.

As shown in Fig. 4, the discharge conduit 68 is divided into separate passageways Na and 1 lb which respectively communicate with a set of discharge openings 12a and 12b. These sets of discharge openings are disposed so as to discharge the binding agent on opposite sides of and near the center of the mixer for mixing with the aggregate therein.

In order to maintain the binding agent in heated condition and facilitate its flow through the valve, pump, and discharge conduit passageways, a jacket '83 may be provided at the outlet of the spout 25. Aninlet steam line 14 may be connected to this jacket and an outlet connection or return 15 carried through the passageway H17 and thence returned along the top of the discharge conduit 68.

In order to prevent the discharge openings 12a and 1229 from becoming occluded or stopped up by material which is being mixed, which under certain conditions might tend to build up until contact is made with the discharge conduits, a bafile member 18 is provided. As shown in Fig. 4, this baffle comprises an angle bar supported in inverted V position and secured at its ends to plate members ll secured as by bolts 18 to the adjacent portions of the collar 22. This baffle further serves to disperse or spread the binding agent over the aggregate as it issues from the discharge openings 12a and 12b, so that a more thorough mixing may be obtained.

There is disclosed a modified conduit discharge structure 68a in Fig. 5, wherein the pump for augmenting flow of binding material has been omitted and flow from the spout 25 being dependent solely upon gravity. In this form of construction, the discharge conduit 68a is of substantially rectangular formation with a diagonal partition 79 which is disposed vertically to separate the conduit into parallel passageways 80a and 80?), as shown in Fig. 6. The passageway 80a communicates with a set of discharge openings 8la and 8| b respectively. The steam return line 75 is carried through the passageway 80a, and then turned back and carried through the passageway 80b.

In Fig. 7 another structure for discharging the binding agent is disclosed. In this arrangement the flow is by gravity and, instead of having the passageways formed in a single discharge conduit, separate conduits are utilized. As shown, a short conduit 82:; communicates with a set of discharge openings 83a, and a longer conduit 822) communicates in its outer end portion with a set of discharge openings 83b.

While the structures disclosed in Figs. 5 and '7 are arranged for gravity flow, it is within the contemplation of the present invention to also utilize an impeller pump, if desired.

I claim as my invention:

1. In apparatus for mixing an aggregate and binding agent: a mixer; a weighing receptacle for receiving and determining a charge of the binding agent; tubular conductor means extending from said receptacle over the mixer with sets of discharge openings disposed on opposite sides of the center of said mixer; a separate passage feeding each set of openings; a shielding bafile between said openings and the mixer; valve means for controlling flow from the receptacle to said passages; and means for heating the valve means and said passages.

2. In apparatus for mixing an aggregate and binding agent: a mixer; a weighing receptacle for receiving and determining a charge of the binding agent; a tubular conductor extending from said receptacle over the mixer with an end portion on one side of its center; a tubular conductor extending from said receptacle over the mixer with an end portion on the other side of its center, said conductors having discharge openings in said end portions; shielding baffles supported below said openings; and a valve for controlling flow from said receptacle to said conductors.

3. In apparatus for mixing an aggregate and binding agent; a mixer; a weighing receptacle for receiving and determining a charge of the binding agent; a plurality of tubular conductors of different lengths extending over said mixer, said conductors having discharge openings disposed above different portions of said mixer; a valve controlling flow from said receptacle to said conductors; and means for maintaining areas adjacent the valve and conductors in heated condition.

4. In apparatus for mixing an aggregate and binding agent: a mixer; a weighing receptacle for receiving and determining a charge of the binding agent; means defining a plurality of discharge passageways extending from said receptacle outwardly over the mixer, each of said passageways communicating with a plurality of discharge openings; valve means for controlling fiow of binding agent from the receptacle into said passageways; a shielding baflie between the mixer and said openings; and heating means associated with said valve and said passageways.

5. In mixing apparatus: a mixer; means above said mixer for guiding a predetermined amount of aggregate into the mixer; a housing extending between said means and mixer; a weighing receptacle outside of said housing for measuring a predetermined amount of liquid binding agent; conductor means extending horizontally over the mixer within the housing defining a plurality of separate passages from said receptacle, each of said passages communicating with discharge openings for discharging binding material from the respective passages into the aggregate in the mixer; pumping means within the housing common to said passages for increasing speed of movement of a weighed charge of binding material from the weighing receptacle into said passages under pressure; electric power means outside said housing; and a power transmitting connection from the power means to the pumping means carried through said housing, said pumping means and power means being supported for weighing movements as a unit with the receptacle and conductor means.

6. In apparatus for mixing an aggregate and binding agent: a mixer; a weighing receptacle for receiving and determining a charge of the binding agent; tubular conductor means extending from said receptacle over the mixer having a plurality of openings for discharging said binder into said mixer; valve means for controlling flow of binder material from said receptacle to the tubular conductor; a power driven impeller downstream from said valve for increasing the pressure of the binder within said conductor; and means for heating the binding material in the vicinity of said impeller.

WALTER M. MADSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

